For the good lord said unto them... "Tell me what it is you want."
And the fools they cried, "We want power. Great power, over people."
But the wise, more importantly, asked of power from a different source. A device that could invoke feelings like no other. A mechanical device, designed by the hands and minds of humans... an engine. An engine that could deliver oodles of power from low revs, and induce wheelies at the slightest provocation. And the diligent were patient, and they duly received.
Four-stroke singles. Word.
Unheard horsepower from a mid-sized single is a great feat. For years they were dull, docile, heavy lumps that were dependable but, essentially, boring. Then they got quick, lightweight, scared the shit out of us, but were slightly unreliable. Because great power comes at great expense...
In time though, we got it all. Including 10,000km service intervals from a single cylinder midsize, pushing out around 66BHP. Stone the crows cobber, I think we're onto something.
The 690 SMC-R.
With great power comes great responsibility.
Funnily enough... grease dries out and goes hard after thirty years of getting mashed in a worm drive, but how do you get the speedo drive apart without ruining the seal? Once they're put together, it's nigh on impossible to remove it — and you can't buy the drive complete now, let alone get the right seal!
So, after a lot of messing around with a spare one I have, I decided to have a stab at getting it apart with minimal damage. I came to the conclusion that a 2.5mm hole drilled through the body of the drive itself would allow access for a small punch to tap out the seal. If all goes to plan, a small dab of silicone in the hole will seal it up once finished. Job jobbed.
Symptoms.
Just turning the tabbed washer will tell you how bad it is. If it stops, gets stuck and generally feels tight, it needs to be stripped, cleaned and greased. Leave it and the tabbed washer will fail, maybe even the worm drive and gear itself. The drive in my ESD has had the tabs brazed back on at some stage. And this spare drive has quite a bit of wear on the inner tabs where it fits into the gear.
Whatever happens, it would be good to take a look inside and see what can be fixed. With a centre pop first, and then very slowly with the drill I had enough room for a small punch to tap on the back of the seal.
